Apparatus and method for randomly controlling time slot of sub-frame in an NB-TDD CDMA system

ABSTRACT

An apparatus randomly assigns downlink sub-frame time slots for transmitting user data in an NB-TDD CDMA (Code Division Multiple Access) communication system. In the apparatus, a multiplexer creates a user data part by multiplexing user data for UEs (User Equipments), a TFCI (Transport Format Combination Indicator) symbol for the user data, and a TPC (Transmission Power Control command) symbol for controlling transmission power of a downlink channel, and a controller randomly assigns time slots for transmitting the user data part in the sub-frames, based on a time slot number initially assigned for the user data part, a sub-frame number at a transmission point of the user data part, and the number of assigned uplink time slots in the corresponding sub-frame.

PRIORITY

This application claims priority to an application entitled “Apparatusand Method for Randomly Controlling Time Slot of Sub-frame in an NB-TDDCDMA System” filed in the Korean Industrial Property Office on Nov. 2,2000 and assigned Serial No. 2000-65054, the contents of which arehereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to an NB-TDD CDMA (Narrow BandTime Division Duplexing Code Division Multiple Access) communicationsystem, and in particular, to an apparatus and method for randomlyassigning time slots of a sub-frame transmitting user data of a userequipment.

2. Description of the Related Art

In an NB-TDD CDMA mobile communication system, a radio networkcontroller (RNC) assigns unique uplink and downlink channels to eachuser equipment (UE) through a physical channel, for radio communicationwith the UE. The UE then transmits frames to a Node B through the uplinkphysical channel assigned thereto, and receives frames transmitted fromthe Node B through the assigned downlink physical channel. In the NB-TDDCDMA mobile communication system, the physical channels transmit 100frames per second. That is, each frame has a size (length) of 10 ms.Further, the frame is divided into two sub-frames, and each sub-frame iscomprised of 7 time slots Ts(0)–Ts(6).

A structure of the sub-frames used in the NB-TDD CDMA mobilecommunication system will be described with reference to FIG. 1. In thefollowing description, the 7 time slots Ts of the sub-frame arerepresented by Ts(0), Ts(1), Ts(2), Ts(3), Ts(4), Ts(5) and Ts(6) fromthe left hand side on a time axis.

Referring to FIG. 1, a sub-frame used in the NB-TDD CDMA mobilecommunication system has a length of 5 msec (=6400 chips). The sub-frameis comprised of 7 normal Ts, a downlink pilot time slot (DwPTS), and anuplink pilot time slot (UpPTS). Each Ts has a length of 864 chips, andthe DWPTS and a guard period (GP) both have a length 96 chips. The UpPTShas a length of 160 chips. Further, the Ts are classified into uplinktime slots and downlink time slots. A common NB-TDD CDMA mobilecommunication system fixedly designates Ts(0) as a downlink time slotand Ts(1) as an uplink time slot. In addition, a “switching point”indicating a boundary between the uplink time slot and the downlink timeslot should occur two times in one sub-frame. The radio networkcontroller determines the number of uplink time slots in the sub-framefor a specific channelization code, and assigns a time slot in responseto a request from the UE. Once the UE is assigned the time slot, itcontinuously uses the assigned time slot until the call is ended. Forexample, if the UE is initially assigned Ts(5), it will transmit datausing only Ts (5).

The term “frame” used in the NB-TDD CDMA mobile communication systemrefers to two consecutive sub-frames, and it has a length of 10 msec.Further, the term “multi-frame configuration (or structure)” refers to amapping relationship between a specific Ts in several consecutive framesand a physical channel, a relationship that is repeated at set periods.

The multi-frame configuration will be described in detail. In themulti-frame configuration, a time slot #0 Ts(0) in each sub-frame can bemapped with a broadcast channel (BCH), a forward access channel (FACH)or a paging channel (PCH). A mapping relationship between Ts(0) and theabove-stated physical channels of BCH, FACH and PCH can be predefined.The multi-frame configuration, as stated above, refers to aconfiguration where a frame is repeated in the common channels of BCH,FACH, PCH and PICH (Pilot Channel). However, since only the BCH isconsidered in the following description, only the configuration wherethe BCH is repeated will be defined as the multi-frame configuration.

In the NB-TDD CDMA mobile communication system, 200 sub-frames persecond are arranged in the physical channel on the time axis at regularintervals, so that a signal transmitted by a specific UE is transmittedat the frequency of exactly 200 times per second. As a result, signalsare concentrated on a frequency of 200 Hz belonging to an audiblefrequency band, causing an electromagnetic interference which mayinterrupt a voice (or circuit) call of the UE.

SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to provide anapparatus and method for randomly assigning a time slot in an uplinksub-frame to a UE in an NB-TDD CDMA mobile communication system.

It is another object of the present invention to provide an apparatusand method for randomly assigning a time slot in an uplink sub-frame toa UE while minimizing electromagnetic interference, in an NB-TDD CDMAmobile communication system.

In accordance with one aspect of the present invention, there isprovided an apparatus for randomly assigning downlink sub-frame timeslots transmitting user data in an NB-TDD CDMA communication systemwhich includes a plurality of frames having different frame numbers,each of the frames including a plurality of sub-frames having differentsub-frame numbers, each of the sub-frames including a plurality of timeslots. The apparatus assigns user data of a plurality of UEs to the timeslots in each sub-frame before transmission. In the apparatus, amultiplexer creates a user data part by multiplexing user data for a UE,a TFCI (Transport Format Combination Indicator) symbol for the userdata, and a TPC (Transmission Power Control command) symbol forcontrolling transmission power of a downlink channel. A controllerrandomly assigns time slots for transmitting the user data part in thesub-frames, based on a time slot number initially assigned for the userdata part, a sub-frame number at a transmission point of the user datapart, and the number of assigned uplink time slots in the correspondingsub-frame.

In accordance with another aspect of the present invention, there isprovided an apparatus for randomly assigning uplink sub-frame time slotstransmitting user data in an NB-TDD CDMA communication system whichincludes a plurality of frames having different frame numbers, each ofthe frames including a plurality of sub-frames having differentsub-frame numbers, each of the sub-frames including a plurality of timeslots. The apparatus assigns user data of a plurality of UEs to the timeslots in each sub-frame before transmission. In the apparatus, amultiplexer creates a user data part by multiplexing user data to betransmitted to a Node B, a TFCI symbol for the user data, and a TPCsymbol for controlling transmission power of an uplink channel. Acontroller randomly assigns time slots for transmitting the user datapart in the sub-frames, based on a time slot number initially assignedfor the user data part, a sub-frame number at a transmission point ofthe user data part, and the number of assigned uplink time slots in thecorresponding sub-frame.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the presentinvention will become more apparent from the following detaileddescription when taken in conjunction with the accompanying drawings inwhich:

FIG. 1 illustrates a common sub-frame structure in an NB-TDD CDMA mobilecommunication system;

FIG. 2 illustrates a method for allocating sub-frame numbers in anNB-TDD CDMA mobile communication system according to an embodiment ofthe present invention;

FIG. 3 illustrates an example of sub-frames transmitted by UEs in thecommon NB-TDD CDMA mobile communication system;

FIG. 4 illustrates an example of a sub-frame time slot configuration inthe NB-TDD CDMA mobile communication system according to a firstembodiment of the present invention;

FIG. 5 illustrates another example of a sub-frame time slotconfiguration in the NB-TDD CDMA mobile communication system accordingto the first embodiment of the present invention;

FIG. 6 illustrates another example of a sub-frame time slotconfiguration in the NB-TDD CDMA mobile communication system accordingto the first embodiment of the present invention;

FIG. 7 illustrates a structure of a UE transceiver for performing anoperation according to an embodiment of the present invention; and

FIG. 8 illustrates a structure of a Node B transceiver for performing anoperation according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

A preferred embodiment of the present invention will be described hereinbelow with reference to the accompanying drawings. In the followingdescription, well-known functions or constructions are not described indetail since they would obscure the invention in unnecessary detail.

FIG. 2 illustrates a method for allocating sub-frame numbers in anNB-TDD CDMA mobile communication system according to an embodiment ofthe present invention. Referring to FIG. 2, the NB-TDD CDMA mobilecommunication system assigns a unique serial number to every sub-frame.Here, the serial number assigned to each sub-frame will be referred toas a “sub-frame number”. The sub-frame number is created using a systemframe number (SFN) assigned to every frame. The sub-frame number isassigned according to Rule (1) below.Sub-frame Number=2*SFN+j {j=0,1}  Rule (1)

In Rule (1), if j=0, the sub-frame number indicates a leading sub-frameout of the sub-frames in the same frame; and if j=1, the sub-framenumber indicates a following sub-frame out of the sub-frames in the sameframe.

Since the SFN has a value of 0 to 4095, the sub-frame number increasesbetween 0 and 8191 in a simple manner, and is expressed with a 13-bitbinary sequence. Further, it is possible for the UE to check the SFNexpressed with a 12-bit binary sequence through a BCH control message.

Before describing an embodiment of the present invention, the terms usedin the following description will be defined below.

(1) “Ts(n)” indicates an n^(th) time slot in a given sub-frame in theNB-TDD CDMA mobile communication system. The value ‘n’, a variablerelated to the sub-frame, is an integer from 0 to 6 since the sub-frameis comprised of 7 time slots.

(2) “Ts(n,i)” indicates an n^(th) time slot in a sub-frame with asub-frame number ‘i’ in the NB-TDD CDMA mobile communication system. Thevalue “i”, another variable related to the sub-frame, is an integerbetween 0 and 8191.

(3) “UL_x” indicates the time slot used by a specific UE x in the NB-TDDCDMA mobile communication system.

(4) “UL_x(i)” indicates a time slot to be used by a specific UE x forthe uplink in a sub-frame with a sub-frame number ‘i’ in the NB-TDD CDMAmobile communication system. UL_x(i) has a value between Ts(1) andTs(6), and ‘i’ is has a value of 0 to 8191 in binary.

(5) “ft_x” indicates a time slot number assigned to a UE x for a call.The time slot number is differently assigned to each of the UEs everytime slot and has a value between 1 and N. The time slot number also hasunique and one to one relationship with the UE it is assigned to.

In the conventional NB-TDD CDMA mobile communication system, if ft_x ofa UE x is ‘m’, the UL_x(i) is continuously fixed to Ts(m) until a callperformed by the UE x is ended. However, the embodiment of the presentinvention changes the UL_x(i) according to the sub-frame number ‘i’ asrepresented by Equation (1).UL _(—) x(i)=Ts[f _(—) x(i)]  (1)

In Equation (1), ‘i’ indicates a sub-frame number at a given time pointof a given system, and f_x(i) indicates an arbitrary function whichdepends on the ft_x and the ‘i’. Although the f_x(i) can be replacedwith various functions, the embodiment of the present invention definesthe f_x(i) as a function given by Equation (2).f _(—) x(i)=[{M[C(i) EOR S]+ft _(—) x} mod N]+1  (2)

In Equation (2), C(i) indicates a function for outputting a 13-bitbinary sequence by receiving a sub-frame number ‘i’ at a given timepoint, and C(i) indicates the sub-frame number ‘i’ expressed in the13-bit binary sequence. Further, ‘S’ indicates an integer having a valuebetween 0 and 8191, and is expressed with one of 13-bit binarysequences. ‘N’ indicates the total number of time slots assigned to theuplink at a given time point of a given system, and EOR indicates anexclusive OR operator operating in a bit unit. M[A] indicates a functiontaking a binary sequence A={a12, a11, a10, . . . a0} as its input value,when an output value of {C(i) EOR S} is a12a11a10 . . . a0, and can berepresented by Equation (3). Here, it is preferable that the functionM[A] should be so determined as to most randomly generate its outputvalue.

$\begin{matrix}{{M\lbrack A\rbrack} = {\sum\limits_{n = 0}^{12}\;{a_{n} \times g_{n}}}} & (3)\end{matrix}$

In addition, when applied to the above-defined f_x(i) function, C(i) isdefined as ‘i’ and g(n) is defined as ‘1’, and the result becomes equalto the number of 1s in the 13-bit binary sequence A. As a result, thefunction M[A] becomes a function of outputting a value determined bycounting the number of 1s in the 13-bit binary sequence.

Therefore, in a first embodiment for randomly assigning an uplink timeslots to a UE, the M[A] is represented by Equation (4), and a method forrandomly assigning a time slot of a sub-frame will be described withreference to Equation (4).

$\begin{matrix}{{M\lbrack A\rbrack} = {\sum\limits_{n = 0}^{12}\; a_{n}}} & (4)\end{matrix}$

An operation according to the first embodiment of the present invention,being dependent on the N value, will be described with reference toFIGS. 4 to 6.

Before describing the operation according to the first embodiment of thepresent invention, an example of sub-frames transmitted by the UEs inthe convention NB-TDD CDMA mobile communication system will be describedwith reference to FIG. 3. FIG. 3 illustrates an example of sub-framestransmitted by the UEs in the common NB-TDD CDMA mobile communicationsystem, and particularly illustrates an exemplary method of transmittingsub-frames for the case of N=4. Since N=4, 4 time slots per sub-frameare designated as uplink time slots, and then used by the UEs of UEa,UEb, and UEc. Each of the UEs uses the initially assigned time slotuntil its call is ended.

Now, a time slot configuration of the sub-frame according to the firstembodiment of the present invention will be described with reference toFIGS. 4 to 6.

First, the description will be made with reference to FIG. 4.

FIG. 4 illustrates an example of a sub-frame time slot configuration inan NB-TDD CDMA mobile communication system according to a firstembodiment of the present invention, and particularly illustrates asub-frame time slot configuration for the case of N=2. In the case ofN=2, if UEa and UEb use uplink time slots, then f_a(i) and f_b(i) forthe sub-frame numbers of 0 to 31 are represented by Table 1, given thata 13-bit binary sequence “010110111010” is selected as the S, ft_a=1 andft_b=2. The sub-frame time slot configuration made based on Table 1 isillustrated in FIG. 4.

TABLE 1 Sub-frame Num f_a(i) f_b(i) 0 1 2 1 2 1 2 2 1 3 1 2 4 2 1 5 1 26 1 2 7 2 1 8 2 1 9 1 2 10 1 2 11 2 1 12 1 2 13 2 1 14 2 1 15 1 2 16 2 117 1 2 18 1 2 19 2 1 20 1 2 21 2 1 22 2 1 23 1 2 24 1 2 25 1 2 26 1 2 271 2 28 2 1 29 1 2 30 1 2 31 2 1

In addition, if N=1 and UEa uses the uplink time slot, the result of‘mod 1’ operation in Equation (2) is always ‘0’. Thus, f_a(i)=1 and thesub-frame is transmitted in the same method as in the conventionalNB-TDD CDMA mobile communication system.

Second, the description will be made with reference to FIG. 5.

FIG. 5 illustrates another example of a sub-frame time slotconfiguration in the NB-TDD CDMA mobile communication system accordingto the first embodiment of the present invention, and more particularlyillustrates a sub-frame time slot configuration for the case of N=3. Inthe case of N=3, if UEa, UEb, and UEc use uplink time slots, thenf_a(i), f_b(i) and f_c(i) for the sub-frame numbers of 0 to 31 arerepresented by Table 2, given that a 13-bit binary sequence“0101110111010” is equally selected as the S, ft_a=1, ft_b=2 and ft_c=3.The sub-frame time slot configuration on Table 2 is illustrated in FIG.5.

TABLE 2 Sub-frame Num f_a(i) f_b(i) f_c(i) 0 3 1 2 1 1 2 3 2 2 3 1 3 3 12 4 2 3 1 5 2 3 1 6 3 1 2 7 1 2 3 8 2 3 1 9 3 1 2 10 3 1 2 11 2 3 1 12 31 2 13 1 2 3 14 2 3 1 15 3 1 2 16 2 3 1 17 3 1 2 18 1 2 3 19 2 3 1 20 12 3 21 1 2 3 22 2 3 1 23 3 1 2 24 1 2 3 25 3 1 2 26 3 1 2 27 1 2 3 28 23 1 29 3 1 2 30 1 2 3 31 2 3 1

Third, the description will be made with reference to FIG. 6.

FIG. 6 illustrates further another example of a sub-frame time slotconfiguration in the NB-TDD CDMA mobile communication system accordingto the first embodiment of the present invention, especially illustratesa sub-frame time slot configuration for the case of N=4. In the case ofN=4, if UEa, UEb, UEc and UEd use uplink slots, then f_a(i), f_b(i),f_c(i) and f_d(i) for the sub-frame numbers of 0 to 31 are representedby Table 3, given that a 13-bit binary sequence “0101110111010” isequally selected as the S, ft_a=1, ft_b=2, ft_c=3 and ft_d=4. Thesub-frame time slot configuration made based on Table 3 is illustratedin FIG. 6.

TABLE 3 Sub-frame Num f_a(i) f_b(i) f_c(i) f_d(i) 0 1 2 3 4 1 2 3 4 1 24 1 2 3 3 1 2 3 4 4 2 3 4 1 5 3 4 1 2 6 1 2 3 4 7 2 3 4 1 8 4 1 2 3 9 12 3 4 10 1 2 3 4 11 4 1 2 3 12 1 2 3 4 13 2 3 4 1 14 4 1 2 3 15 1 2 3 416 4 1 2 3 17 1 2 3 4 18 3 3 4 1 19 4 1 2 3 20 3 4 1 2 21 2 3 4 1 22 4 12 3 23 1 2 3 4 24 3 4 1 2 25 1 2 3 4 26 1 2 3 4 27 3 4 1 2 28 4 1 2 3 291 2 3 4 30 3 4 1 2 31 4 1 2 3

Further, even in the case of N=5 and N=6, the sub-frame time slotconfiguration can be applied in the same manner as in the case of N=4.

The assignment configuration of the sub-frame time slots according tothe first embodiment where the M[A] is applied as defined by Equation(4), has been described with reference to FIGS. 4 to 6. Next, asub-frame time slot configuration according to a second embodiment ofthe present invention will be described.

In the second embodiment of the present invention, the M[A] will bedefined in the different form from that of the first embodiment of thepresent invention. That is, when applied to the function f_x(i), C(i) isdefined as ‘i’, and g(n) is defined as 2^(n). As a result, the M[A]according to the second embodiment of the present invention isrepresented by Equation (5), and a method for randomly assigning a timeslot of a sub-frame according to the second embodiment will be describedwith reference to Equation (5).

$\begin{matrix}{{M\lbrack A\rbrack} = {\sum\limits_{n = 0}^{12}\;{a_{n} \times 2^{n}}}} & (5)\end{matrix}$

In equation (5), the function M[A] becomes a function of outputting adecimal number obtained by converting a 13-bit binary sequence.

An operation according to the second embodiment of the presentinvention, being dependent on the N value, will be described.

In the case of N=2, if UEa and UEb are assigned Ts(1) and Ts(2) as theiruplink time slots, respectively, then f_a(i) and f_b(i) for thesub-frame numbers of 0 to 31 are represented by Table 4, given that“1101100101101” out of 13-bit binary sequences is selected as the S.

TABLE 4 Sub-frame Num f_a(i) f_b(i) 0 1 2 1 2 1 2 1 2 3 2 1 4 1 2 5 2 16 1 2 7 2 1 8 1 2 9 2 1 10 1 2 11 2 1 12 1 2 13 2 1 14 1 2 15 2 1 16 1 217 2 1 18 1 2 19 2 1 20 1 2 21 2 1 22 1 2 23 2 1 24 1 2 25 2 1 26 1 2 272 1 28 1 2 29 2 1 30 1 2 31 2 1

Even in the case of N=1, 3, 4, 5 and 6, the f_x(i) is calculated andapplied in the same manner as in the case of N=2.

The assignment configuration of the sub-frame time slots according tothe second embodiment where the M[A] is applied as defined by Equation(5), has been described. Next, a sub-frame time slot configurationaccording to a third embodiment of the present invention will bedescribed.

In the third embodiment of the present invention, the M[A] will bedefined in the different form from that of the first and secondembodiments of the present invention. That is, when applied to thefunction f_x(i), C(i) is defined as ‘i’, and g(n) is defined as (n+1).As a result, the M[A] is represented by Equation (6), and a method forrandomly assigning a time slot of a sub-frame according to the thirdembodiment will be described with reference to Equation (6).

$\begin{matrix}{{M\lbrack A\rbrack} = {\sum\limits_{n = 0}^{12}\;{a_{n} \times \left( {n + 1} \right)}}} & (6)\end{matrix}$

In the case of N=2, if UEa and UEb are assigned Ts(1) and Ts(2) as theiruplink time slots, respectively, as in the second embodiment of thepresent invention, then f_a(i) and f_b(i) for the sub-frame numbers of 0to 31 are represented by Table 5, given that “1101100101101” out of13-bit binary sequences is selected as the S.

TABLE 5 Sub-frame Num f_a(i) f_b(i) 0 1 2 1 2 1 2 2 1 3 1 2 4 2 1 5 1 26 1 2 7 2 1 8 2 1 9 1 2 10 1 2 11 2 1 12 1 2 13 2 1 14 2 1 15 1 2 16 2 117 1 2 18 1 2 19 2 1 20 1 2 21 2 1 22 2 1 23 1 2 24 1 2 25 2 1 26 2 1 271 2 28 2 1 29 1 2 30 1 2 31 2 1

The assignment configuration of the sub-frame time slots according tothe third embodiment where the M[A] is applied as defined by Equation(6), has been described. Next, a sub-frame time slot configurationaccording to a fourth embodiment of the present invention will bedescribed.

In the fourth embodiment of the present invention, the M[A] will bedefined in the different form from that of the first, second and thirdembodiments of the present invention. That is when applied to thefunction f_x(i), C(i) is defined as ‘(i+2^(i)) mod 8192’, and g(n) isdefined as 2^(n). As a result, the M[A] is represented by Equation (7),and a method for randomly assigning a time slot of a sub-frame accordingto the fourth embodiment will be described with reference to Equation(7).

$\begin{matrix}{{M\lbrack A\rbrack} = {\sum\limits_{n = 0}^{12}\;{a_{n} \times 2^{n}}}} & (7)\end{matrix}$

In the case of N=3, if UEa, UEb and UEc use time slots, then f_a(i),f_b(i) and f_c(i) for the sub-frame numbers of 0 to 31 are representedby Table 6, given that “1101100101101” out of 13-bit binary sequences isselected as the S.

TABLE 6 Sub-frame Num f_a(i) f_b(i) f_c(i) 0 1 2 3 1 2 3 1 2 3 1 2 3 1 23 4 2 3 1 5 1 2 3 6 1 2 3 7 2 3 1 8 2 3 1 9 3 1 2 10 3 1 2 11 2 3 1 12 12 3 13 1 2 3 14 3 1 2 15 2 3 1 16 1 2 3 17 2 3 1 18 3 1 2 19 2 3 1 20 12 3 21 3 1 2 22 1 2 1 23 3 1 3 24 2 3 1 25 2 3 1 26 2 3 1 27 1 2 3 28 23 1 29 2 3 1 30 3 1 2 31 2 3 1

Further, even in the case of N=1, 2, 4, 5 and 6, the sub-frame time slotconfiguration can be applied in the same manner as in the case of N=3.

A description will now be made of a communication procedure between theUE, which randomly controls transmission points of the uplink time slotsin the sub-frame, and a UTRAN (UMTS (Universal Mobile TelecommunicationSystem) Terrestial Radio Access Network). Of course, the function f_x(i,S, N, ft_x) used to randomly assign the sub-frame time slots should bepredefined between physical layers of a UE and a Node B.

First, a description will be made of an operating process of the UE.

1. Operating Process of UE

(1) Cell search is performed.

(2) A radio resource control (RRC) layer of a UE which has acquiredsynchronization with a cell to which the UE belongs and also acquiredBCH access information through the cell search, receives the followinginformation over the BCH.

Number ‘N’ of uplink time slots per sub-frame

EMI (Electromagnetic Indicator) indicator

‘S’ used to randomly assign time slots

However, the value S is not transmitted when the corresponding cell doesnot support the method for randomly assigning the sub-frame time slot orthe UE and the UTRAN previously recognize the S value.

(3) The RRC layer of the UE transmits an upper layer message requestingassignment of a dedicated channel (DCH). Herein, an RB SETUP (RadioBarer SETUP) message will be used for the upper layer message. Adetailed description of a transmission format of the upper layer messageand a primitive of the message will be omitted.

(4) The RRC layer of the UE receives the RB SETUP message, and thendetects ft_x using information on Uplink Timeslots and Codes fromInformaion Element(IE) of the RB SETUP message.

(5) If the received EMI indicator indicates use of a random time slotdetermination method, the RRC layer of the UE transmits S, N and ft_x toa controller of the physical layer, and then informs the controller thatthe random time slot determination method will be applied. For thecommunication between the RRC layer of the UE and the physical layer,CPHY-RL-Setup-REQ can be used as a primitive. It can be used forinter-layers communication as a message. That is, in order to randomlydetermine the time slot of the UE, the RRC layer of the UE can receiveinformation on the initial uplink time slot from the Node B and thenprovide the received information to the controller which controls thetime slots of the physical layer. In addition, the UE can either receivethe EMI indicator through an NBAP (Node B Application Part) message froma radio network controller (RNC), or receive information on the EMIindicator along with the information on the initial uplink time slotduring cell setup.

(6) Upon receipt of the initial uplink time slot from the Node B, thephysical layer controller of the UE calculates f_x(i, S, N, ft_x) usingthe receive information, and randomly determines the time slot assignedto the UE using the calculated value, before transmission.

2. Operating Process of UTRAN

(1) An RRC layer of the radio network controller provides information onthe number N of the time slots to be used for the uplink to a Node B ofthe corresponding cell, using a timeslot configuration InformationElement(IE) of a Cell Setup Request message. The Node B transmits theprovided N to a controller of the physical layer through an NBAPmessage. In this case, if the S value has not been previouslydetermined, the Node B can transmit the S value along with the N value.

(2) The RRC layer of the radio network controller periodically transmitsthe information described in the process (2) of the UE operating processalong the BCH in the same manner as in the conventional NB-TDD CDMAsystem. Alternatively, the Node B can provide information on the EMIindicator while providing the initial uplink time slot to be used by theUE.

(3) The RRC layer of the radio network controller receives an RAB (RadioAccess Bearer) Assignment Request message or an RAB Modification Requestmessage from a core network (CN). If it is necessary to assign adedicated channel (DCH), the RRC layer of the radio network controllertransmits the RB Setup message to the RRC layer of the UE.

(4) Upon receiving the RB Setup message, the RRC layer of the UEtransmits an RB Setup Complete message to the radio network controllerin response to the RB Setup message. Upon receiving the RB SetupComplete message, the radio network controller transmits a Radio LinkSetup message to a Node B in the corresponding cell. The Node B thendetermines ft_x using the timeslot configuration IE of the uplinkdedicated physical channel (UL-DPCH) information of the NBAP message,and provides the determined value to the controller of the physicallayer.

(5) The physical layer of the Node B recognizes a time slot to be usedby a specific UE by calculating f_x(i, S, N, ft_x) for the UE. In thismanner, the Node B recognizes the sub-frame time slot randomlytransmitted by the UE, and prepares to receive user data transmitted bythe UE.

Next, a transceiver structure of the UE and the Node B for randomizingthe uplink time slot, i.e., randomly changing the uplink time slot ofeach UE in the sub-frame thereby to solve the electromagneticinterference problem, will be described with reference to FIGS. 7 and 8.

FIG. 7 illustrates a structure of a UE transceiver for performing anoperation according to an embodiment of the present invention, and FIG.8 illustrates a structure of a Node B transceiver for performing anoperation according to an embodiment of the present invention. For thesake of convenience, it is assumed in FIGS. 7 and 8 that communicationis performed between a Node B and an i^(th) UE in the Node B. However,communication between a Node B and another UE in the Node B can also beperformed in the same manner.

First, a structure of the UE transceiver will be described withreference to FIG. 7.

In general, since the NB-TDD CDMA mobile communication system uses thesame frequency band for both uplink transmission and downlinktransmission, a transmitter is separated from a receiver by a switch.First, a structure of the transmitter in the UE transceiver of FIG. 7will be described.

i^(th) user's data 701 to be transmitted to the Node B through the UE isprovided to an encoder 702. The encoder 702 channel-codes the receiveduser data 701 with a convolutional code or a channelization code, andprovides the channel-coded user data to an interleaver 703. Theinterleaver 703 interleaves the i^(th) user's data channel-coded by theencoder 702 according to a predefined rule, and provides the interleaveduser data to a multiplexer (MUX) 706. Here, the interleaver 703rearranges (or interleaves) the i^(th) channel-coded user data accordingto the predefined rule, so that possible narrow band interference isdespersed after deinterleaving, thus minimizing the effects of thenarrow band interference.

The multiplexer 706 receives an output signal of the interleaver 703, atransmit power control command (hereinafter, referred to as “TPC”) 705,a transmit format combination indicator (TFCI) 704 and SS 760, and thenmultiplexes the output signal of the interleaver 703 and the receivedTPC 705, TFCI 704 and Synchronization Shift(SS) 760 into a slot formatfor the NB-TDD CDMA communication system. Here, the TPC 705 is a commandfor controlling transmission power of the downlink transmitted from theNode B to the UE, and the TFCI 704 is a codeword indicating a transmitformat combination indicator of various data included in the i^(th)user's data transmitted from the UE. Further, the SS 760 is a commandused to control synchronization of a downlink signal. In addition, thesignal obtained by multiplexing of the TFCI 704, TPC 705 and SS 760,output from the multiplexer 706, and the output signal of theinterleaver 703, will be referred to as a “user data part”. The i^(th)user's data part output from the multiplexer 706 is provided to thespreader 707. The spreader 707 spreads the i^(th) user's data part bymultiplying it by a channelization code C_(OVSF), and provides itsoutput to a multiplier 708. For example, an OVSF (Orthogonal VariableSpreading Factor) code is used for the channelization code used in thespreader 707, and the OVSF code is an orthogonal code, a length of whichis determined depending on a data rate of the data. The channelizationcode serves to identify an uplink channel of each UE, when a pluralityof UEs simultaneously transmit the data in one time slot in the NB-TDDCDMA mobile communication system. Further, according to its length, thechannelization code serves to spread a band where the user data from theUE is transmitted.

The i^(th) user's data part, channel-spread with the OVSF code, ismultiplied by a channel gain parameter by the multiplier 708, and thenprovided to a multiplier 709. Here, the channel gain parameter serves todetermine transmission power of an uplink channel for the i^(th) user'sdata, and is determined based on the type of data transmitted throughthe i^(th) user's data part and the TPC transmitted from the Node B. Themultiplier 709 multiplies the i^(th) user's data part output from themultiplier 708 by a scrambling code C_(SCRAMBLE), and provides thescrambled data to a multiplexer 711. Here, the scrambling codeC_(SCRAMBLE), a code used in the 3^(rd) generation asynchronous mobilecommunication standard, is used to identify Node B, identify UE anddecrease a multipath cross correlation of the same signal. In the NB-TDDCDMA mobile communication system, the scrambling code is used only toidentify the Node B and decrease the cross correlation. In the NB-TDDCDMA mobile communication system, each Node B uses one scrambling code,and the scrambling code is used for both the uplink transmission and thedownlink transmission. That is, the multiplier 709 serves as ascrambler.

The multiplexer 711 multiplexes the output signal of the multiplier 709and a midamble 710, and provides the multiplexed signal to a modulator712. The output signal of the multiplexer 711 becomes an i^(th) user'suplink channel signal, and a basic transmission unit of the i^(th)user's uplink channel becomes a time slot. The i^(th) user's uplinkchannel is comprised of the user data 701, the TPC 705, the TFCI 704,the midamble 710 and the guard period (GP). The midamble 710 is used formulti-user detection supported in the NB-TDD CDMA mobile communicationsystem and for channel estimation. The guard period is created toprevent generation of an interference noise between the uplinktransmission and the downlink transmission due to an overlap of theuplink time slot and the downlink time slot in the NB-TDD CDMA mobilecommunication system. Actually, no signal is transmitted in the guardperiod.

The modulator 712 modulates the output signal of the multiplexer 711,i.e., the i^(th) user's uplink channel output, using QPSK (QuadraturePhase Shift Keying), 8PSK (8-ary Phase Shift Keying), or QAM (QuadratureAmplitude Modulation), and provides the modulated signal to a switch720. The switch 720 is switched on at a slot where the i^(th) user'suplink channel is to be transmitted, thereby to transmit the i^(th)user's uplink channel to the Node B. Further, the switch 720 iscontrolled by a controller 721, and the controller 721 controls anuplink channel transmission point, i.e., a sub-frame time slot to betransmitted, according to the first to fourth embodiment of the presentinvention, and also controls a transmission point of UpPTS and areception point of DwPTS according to the sub-frame structure of theNB-TDD CDMA mobile communication system, i.e., controls a receptionpoint of a downlink channel transmitted from the Node B to the UE. Inaddition, the controller 721 calculates the uplink channel transmissionpoint, using f_x(i,S,N,ft_x) recognized by the controller 721 and thevalues N, S and ft_x transmitted from the RRC layer of the Node B.

An UpPTS generator 731 creates UpPTS and provides the created UpPTS tothe switch 720. The UpPTS is transmitted when the UE is required to beassigned a channel from the Node B, or in a handover (or handoff)condition, and is used by the Node B in controlling uplink transmissionpower of the UE or uplink transmission synchronization. The DwPTS isreceived by the UE to initially search the Node B, and serves toindicate the position of a primary common control physical channel(P-CCPCH) transmitting the BCH containing the system information and theposition of the currently received downlink frame in the multi-frameconfiguration. In addition, in the NB-TDD CDMA mobile communicationsystem, the Node B transmits and receives data by scheduling apredetermined number of 10 ms radio frames. In this case, 64 radioframes or 72 radio frames constitute one multi-frame. Therefore, theuplink channel output from the switch 720 is transmitted to the Node Bthrough an antenna 723 after being converted to a carrier frequency bandby an RF (Radio Frequency) processor 722.

Heretofore, the structure of the UE transmitter has been described.Next, a structure of the UE receiver for receiving a downlink channelfrom the Node B will be described with reference to FIG. 7.

A downlink channel signal received through the antenna 723 is providedto the RF processor 722. The RF processor 722 down-converts the outputsignal of the antenna 723 to a baseband frequency, and provides itsoutput to the switch 720. The switch 720, under the control of thecontroller 721, is switched on at a reception point of the downlinkchannel signal, to provide the output signal of the RF processor 722 toa demodulator 732. The downlink channel signal received at the i^(th) UEfrom the Node B may include DwPTS, and the switch 720 provides theoutput signal of the RF processor 722 to a DwPTS analyzer 731 at areception point of the DwPTS. The DwPTS analyzer 731 detects a positionof the BCH and a position of the currently received downlink frame inthe multi-frame configuration by analyzing the received DwPTS. Thedemodulator 732 demodulates the modulated user data part in ademodulation mode corresponding to the modulation mode of the QPSK, 8PSKor QAM modulation used by the Node B, and provides the demodulatedsignal to a demultiplexer 733. The demultiplexer 733 demultiplexes theoutput signal of the demodulator 732 into a midamble 734 and a user datapart, and provides the user data part to a multiplier 735. The midamble734 is used to measure a reception power level of the downlink channeltransmitted from the Node B, and indicates the type of the downlinkchannel transmitted from the Node B. Thus, it is possible to determinewhether there is data transmitted to the UE, by simply analyzing themidamble 734.

The multiplier 735 descrambles the user data part output from thedemultiplexer 733 by multiplying it by a scrambling code C_(SCRAMBLE)identical to the scrambling code used by the Node B, and provides thedescrambled user data part to a despreader 736. The despreader 736separates user data, system information of the Node B, or controlinformation for the UE from the descrambled user data part output fromthe multiplier 735, despreads the spread user data and the downlinkcommon channel, and then provides the despread signal to a demultiplexer38. The despreader 736 separates the user data part, i.e., the user dataand the downlink common channel, by multiplying the output signal of themultiplier 735 by the same OVSF code C_(OVSF) as the OVSF code used inthe Node B.

The i^(th) user's data output from the despreader 736 is provided to thedemultiplexer 738, and the demultiplexer 738 demultiplexes the i^(th)user's data output from the despreader 736 into TPC 739, TFCI 740, SS770 and pure user data. The TPC 739 is used in controlling transmissionpower of the uplink channel to be transmitted by the i^(th) UE, and theTFCI 740 is used in analyzing a transmit format combination indicator ofdata transmitted from the Node B to the i^(th) UE. Further, the SS 770is used as a command generated by the Node B to request synchronizationcontrol of the uplink channel transmitted by the UE. The i^(th) pureuser data output from the demultiplexer 738 is provided to adeinterleaver 741. The deinterleaver 741 deinterleaves the user dataoutput from the demultiplexer 738 and provides the deinterleaved userdata to a decoder 742. The decoder 742 channel-decodes the output signalof the deinterleaver 741, thereby detecting i^(th) user's data 743originally transmitted from the Node B.

The controller 721, which controls the switch 720, randomly sets thetransmission point of the uplink channel according to the first tofourth embodiment of the present invention, and thus minimizes theelectromagnetic interference felt by the user while performing a callthrough the i^(th) UE. That is, the electromagnetic interference of theaudible frequency band is removed by randomly controlling thetransmission point of the uplink and downlink user data from/to the UE.The controller 721 determines whether the Node B in communication withthe i^(th) UE performs an operation of reducing the electromagneticinterference, by analyzing the EMI indicator transmitted over the BCH,and then determines whether to perform its uplink transmission. During ahandover, the UE does not read the BCH from a target Node B to which theUE is handed over, so that the UTRAN can indicate whether the targetNode B performs the electromagnetic interference reducing operation,using a handover message or an active set update message. Here, the term“UTRAN” refers to all the elements of the 3^(rd) generation asynchronousmobile communication system, excepting the UEs. In the embodiment of thepresent invention, the controller minimizes the electromagneticinterference by randomly setting the uplink time slot point both in theNode B and the UE in the same manner. Thus, the Node B can exactlydetermine the reception point of the uplink channel transmitted from theUE.

Now, a description will be made of a transceiver structure of the Node Bwith reference to FIG. 8.

First, a transmitter structure of the Node B transceiver shown in FIG. 8will be described.

i^(th) user's downlink data 801 to be transmitted to the i^(th) UE isprovided to an encoder 802. The encoder 802 channel-codes the receiveddownlink user data 801 and provides the channel-coded signal to aninterleaver 803. The interleaver 803 interleaves the output signal ofthe encoder 802 according to a predetermined rule, and provides theinterleaved signal to a multiplexer (MUX) 806. The multiplexer 806creates an i^(th) user's data part by multiplexing the downlink userdata for the i^(th) UE, output from the interleaver 803, the TPC 805 forcontrolling uplink transmission power of the i^(th) UE, the TFCI 804indicating a transport format used for the i^(th) user's data, and theSS 860 requesting synchronization control of the uplink transmissionchannel from the UE, and provides its output to a spreader 807. Thespreader 807 channel-spreads the i^(th) user's data part output from themultiplexer 806 with a channelization code, e.g., an OVSF code C_(OVSF),used for the downlink channel from the i^(th) UE, and provides thespread signal to a multiplier 808. The multiplier 808 multiplies theoutput signal of the spreader 807 by a channel gain parameter set fortransmission power of the downlink channel to be transmitted to thei^(th) UE, and provides its output to a summer 811. The summer 811 sumsthe output signal (i.e., the i^(th) user's downlink channel) of themultiplier 808, a downlink common channel 810 and another user'sdownlink channel 809, and provides its output to a multiplier 812. Thechannels summed by the summer 811 are channel-spread with different OVSFcodes, so that the channels, even though they are summed, do not affecteach other. The multiplier 812 scrambles the output signal of the summer811 with the scrambling code C_(SCRAMBLE) identical to that used in theNode B, and provides its output to a multiplexer 814. The multiplexer814 creates a downlink channel time slot by multiplexing the downlinkchannel signals output from the multiplier 812 and a received midamble813, and provides its output to a modulator 815. The midamble 813 can beused when the UE having received the midamble 813 estimates atransmission power level of the Node B, and also used to indicate thechannels transmitted over the downlink channel time slot multiplexed bythe multiplexer 814.

The modulator 815 modulates the downlink channel signals output from themultiplexer 814 and provides the modulated signals to a switch 820. Themodulation mode performed by the modulator 815 includes BPSK (BinaryPhase Shift Keying), QPSK, 8PSK and QAM. The switch 820, under thecontrol of a controller 821, is connected to the modulator 815 at atransmission point of the downlink channel time slot, to transmit thedownlink channel time slot to an RF processor 822. That is, the switch820 is switched on to the modulator 815 only at the transmission pointof the downlink channel time slot, under the control of the controller821, thereby to transmit the downlink channel time slot to the RFprocessor 822. In addition, the switch 820, under the control of thecontroller 821, is switched to a DwPTS generator 816 and transmits DwPTScreated by the DwPTS generator 816 at a transmission point of the DwPTS.Here, the DwPTS is used in estimating a position of the BCH includingNode B information, a level of the signal from the Node B, and aposition of a currently received frame in the multi-frame in an initialNode B search process by the UE having received the DwPTS. The RFprocessor 822 converts the downlink channel time slot to a carrier band,and transmits its output to an antenna 823. The antenna 823 transmitsthe downlink channel time slot in the carrier band, output from the RFprocessor 822, to the corresponding UEs.

Next, a receiver structure of the Node B transceiver shown in FIG. 8will be described.

Uplink channel signals received from the UEs through the antenna 823 areprovided to the RF processor 822. The RF processor 822 converts thecarrier band signal output from the antenna 823 to a baseband frequencysignal, and provides the baseband frequency signal to the switch 820.The switch 820, under the control of the controller 821, is switched onto a demodulator 831 at a predetermined reception point to receive theuplink signals transmitted from the UE. The controller 821 operates inthe same way as the controller 721 of the UE shown in FIG. 7. That is,the controller 821 selects one of the first to fourths embodiments,determines uplink channel signal transmission points by the UEs in theNode B according to the selected embodiment, i.e., the uplink channelsub-frame time slots transmitted by the UEs, and then controls theswitch 820 according to the determined results. The controller 821 canexactly determine the reception point of the uplink signals from the UEsin the Node B by selecting one of the embodiments of the presentinvention depending on an electromagnetic interference reductionindicator transmitted from the UTRAN to the Node B. In addition, thecontroller 821 switches the switch 820 to an UpPTS analyzer 830 at areception point of the UpPTS, to allow the UpPTS analyzer 830 to analyzethe UpPTSs transmitted from the UEs.

The demodulator 831 demodulates the received uplink user data part andprovides the demodulated signal to a demultiplexer 832. Thedemultiplexer 832 demultiplexes the output signal of the demodulator 831into a midamble 833 and a pure uplink user data part, and provides theseparated uplink user data part to a multiplier 834. The midamble 833 isused in estimating a channel environment between the UE and the Node B,and a power level of the signal transmitted from the UE. The multiplier834 descrambles the output signal of the demultiplexer 832 bymultiplying it by the same scrambling code C_(SCRAMBLE) as thescrambling code used by the UE transceiver of FIG. 7, and provides itsoutput to a despreader 835. The despreader 835 despreads the outputsignal of the multiplier 834 into uplink user data parts of therespective UEs, and provides an i^(th) user's uplink signal data partamong the separated uplink user data parts to a demultiplexer 836. Thedemultiplexer 836 demultiplexes the uplink user data part from thei^(th) UE into TPC 837, TFCI 838, SS 870 and i^(th) user's data, andprovides the i^(th) user's data to a deinterleaver 839. The TPC 837 isused in controlling a power level of a downlink transmission signal tothe i^(th) UE, and the TFCI 838 is used in analyzing a transport formatused for the user data part from the i^(th) UE. Further, the SS 870 isused in controlling a transmission point of the downlink channel to theUE. The deinterleaver 839 deinterleaves the i^(th) user's data outputfrom the demultiplexer 836, and provides the deinterleaved user data toa decoder 840. The decoder 840 decodes the i^(th) user's data outputfrom the deinterleaver 839, thereby detecting the i^(th) user's uplinkdata 841 transmitted from the i^(th) UE. Another user's uplink data 850output from the despreader 835 is also detected by the Node B throughthe same process as the i^(th) user's data.

The NB-TDD CDMA mobile communication system according to the presentinvention randomly sets the sub-frame time slots for transmitting userdata of the UE and the Node B, thereby removing the electromagneticinterference noise, an intermittence noise of the audible frequency banddue to periodic signal transmission, which may occur when a sub-frametime slot initially assigned during call setup is maintained until thecall is ended. Therefore, the NB-TDD CDMA mobile communication systemhas improved QoS (Quality of Service).

While the invention has been shown and described with reference to acertain preferred embodiment thereof, it will be understood by thoseskilled in the art that various changes in form and details may be madetherein without departing from the spirit and scope of the invention asdefined by the appended claims.

1. An apparatus for randomly assigning downlink sub-frame time slotstransmitting user data in an TDD (Time Division Duplexing) communicationsystem which includes a plurality of frames having different framenumbers, each of the frames including a plurality of sub-frames havingdifferent sub-frame numbers, each of the sub-frames including aplurality of time slots, said apparatus assigns user data of a pluralityof user equipments (UEs) to the time slots in each sub-frame, theapparatus comprising: a multiplexer for creating a user data part bymultiplexing user data for a UE, a TFCI (Transport Format CombinationIndicator) symbol for the user data, and a TPC (Transmission PowerControl command) symbol for controlling transmission power of a downlinkchannel; and a controller for randomly assigning time slots fortransmitting the user data part in the sub-frames, based on a time slotnumber initially assigned for the user data part, a sub-frame number ata transmission point of the user data part, and the number of assigneduplink time slots in the corresponding sub-frame.
 2. The apparatus asclaimed in claim 1, wherein the controller assigns, as a time slotnumber for transmitting the user data part, a fourth value determined byadding the number of downlink time slots in the sub-frame to a thirdvalue obtained by performing a modulo operation with the number of theuplink time slots on a second value determined by adding the initiallyassigned time slot number to a first value generated from a functionhaving an input value determined by exclusive ORing (XOR) a binarysequence corresponding to the sub-frame number and an arbitrary binarysequence among binary sequences having the same length as the binarysequence corresponding to the sub-frame number.
 3. The apparatus asclaimed in claim 2, wherein the function is represented by,${M\lbrack A\rbrack} = {\sum\limits_{n = 0}^{12}\; a_{n}}$ where A is avalue obtained by XORing the binary sequence corresponding to thesub-frame number and an arbitrary binary sequence among binary sequenceshaving the same length as the binary sequence corresponding to thesub-frame number.
 4. The apparatus as claimed in claim 2, wherein thefunction is represented by,${M\lbrack A\rbrack} = {\sum\limits_{n = 0}^{12}\;{a_{n} \times 2^{n}}}$where A is a value obtained by XORing the binary sequence correspondingto the sub-frame number and an arbitrary binary sequence among binarysequences having the same length as the binary sequence corresponding tothe sub-frame number.
 5. The apparatus as claimed in claim 2, whereinthe function is represented by,${M\lbrack A\rbrack} = {\sum\limits_{n = 0}^{12}\;{a_{n} \times \left( {n + 1} \right)}}$where A is a value obtained by XORing the binary sequence correspondingto the sub-frame number and an arbitrary binary sequence among binarysequences having the same length as the binary sequence corresponding tothe sub-frame number.
 6. An apparatus for randomly assigning uplinksub-frame time slots transmitting user data in an TDD (Time DivisionDuplexing) communication system which includes a plurality of frameshaving different frame numbers, each of the frames including a pluralityof sub-frames having different sub-frame numbers, each of the sub-framesincluding a plurality of time slots, said apparatus assigns user data ofa plurality of UEs (User Equipments) to the time slots in eachsub-frame, the apparatus comprising: a multiplexer for creating a userdata part by multiplexing user data to be transmitted to a Node B, aTFCI (Transport Format Combination Indicator) symbol for the user data,and a TPC (Transmission Power Control command) symbol for controllingtransmission power of an uplink channel; and a controller for randomlyassigning time slots for transmitting the user data part in thesub-frames, based on a time slot number initially assigned for the userdata part, a sub-frame number at a transmission point of the user datapart, and the number of assigned uplink time slots in the correspondingsub-frame.
 7. The apparatus as claimed in claim 6, wherein thecontroller assigns, as a time slot number for transmitting the user datapart, a fourth value determined by adding the number of downlink timeslots in the sub-frame to a third value obtained by performing a modulooperation with the number of the uplink time slots on a second valuedetermined by adding the initially assigned time slot number to a firstvalue generated from a function having an input value determined byexclusive ORing (XORing) a binary sequence corresponding to thesub-frame number and an arbitrary binary sequence among binary sequenceshaving the same length as the binary sequence corresponding to thesub-frame number.
 8. The apparatus as claimed in claim 7, wherein thefunction is represented by,${M\lbrack A\rbrack} = {\sum\limits_{n = 0}^{12}\; a_{n}}$ where A is avalue obtained by XORing the binary sequence corresponding to thesub-frame number and an arbitrary binary sequence among binary sequenceshaving the same length as the binary sequence corresponding to thesub-frame number.
 9. The apparatus as claimed in claim 7, wherein thefunction is represented by,${M\lbrack A\rbrack} = {\sum\limits_{n = 0}^{12}\;{a_{n} \times 2^{n}}}$where A is a value obtained by XORing the binary sequence correspondingto the sub-frame number and an arbitrary binary sequence among binarysequences having the same length as the binary sequence corresponding tothe sub-frame number.
 10. The apparatus as claimed in claim 7, whereinthe function is represented by,${M\lbrack A\rbrack} = {\sum\limits_{n = 0}^{12}\;{a_{n} \times \left( {n + 1} \right)}}$where A is a value obtained by XORing the binary sequence correspondingto the sub-frame number and an arbitrary binary sequence among binarysequences having the same length as the binary sequence corresponding tothe sub-frame number.
 11. An apparatus for receiving a downlink signalof randomly assigned sub-frame time slots transmitting user data in anTDD (Time Division Duplexing) communication system which includes aplurality of frames having different frame numbers, each of the framesincluding a plurality of sub-frames having different sub-frame numbers,each of the sub-frames including a plurality of time slots, and assignsuser data of a plurality of UEs (User Equipments) to the time slots ineach sub-frame, the apparatus comprising: a controller for determiningreception sub-frame time slots in association with the randomly assignedsub-frame time slots, based on a time slot number initially assigned ata reception point of the downlink signal and a sub-frame number at thereception point; and a demultiplexer for demultiplexing the downlinksignal received at the reception sub-frame time slots, and outputtinguser data, a TFCI (Transport Format Combination Indicator) symbol forthe user data, and a TPC (Transmission Power Control command) symbol forcontrolling transmission power of a downlink channel.
 12. An apparatusfor receiving uplink signals of randomly assigned sub-frame time slotstransmitting user data in an TDD (Time Division Duplexing) communicationsystem which includes a plurality of frames having different framenumbers, each of the frames including a plurality of sub-frames havingdifferent sub-frame numbers, each of the sub-frames including aplurality of time slots, and assigns user data of a plurality of UEs(User Equipments) to the time slots in each sub-frame, the apparatuscomprising: a controller for determining reception sub-frame time slotsin association with the randomly assigned sub-frame time slots, based ona time slot number initially assigned at a reception point of the uplinksignals and a sub-frame number at the reception point; and ademultiplexer for demultiplexing the uplink signals received at thereception sub-frame time slots, and outputting user data, a TFCI(Transport Format Combination Indicator) symbol for the user data, and aTPC (Transmission Power Control command) symbol for controllingtransmission power of an up link channel.
 13. A method for randomlyassigning downlink sub-frame time slots transmitting user data in an TDD(Time Division Duplexing) communication system which includes aplurality of frames having different frame numbers, each of the framesincluding a plurality of sub-frames having different sub-frame numbers,each of the sub-frames including a plurality of time slots, and assignsuser data of a plurality of UEs (User Equipments) to the time slots ineach sub-frame, the method comprising the steps of: creating a user datapart by multiplexing user data for a UE, a TFCI (Transport FormatCombination Indicator) symbol for the user data, and a TPC (TransmissionPower Control command) symbol for controlling transmission power of adownlink channel; and randomly assigning time slots for transmitting theuser data part in the sub-frames, based on a time slot number initiallyassigned for the user data part, a sub-frame number at a transmissionpoint of the user data part, and the number of assigned uplink timeslots in the corresponding sub-frame.
 14. The method as claimed in claim13, wherein the step of randomly assigning the time slots comprises thestep of assigning, as a time slot number for transmitting the user datapart, a fourth value determined by adding the number of downlink timeslots in the sub-frame to a third value obtained by performing a modulooperation with the number of the uplink time slots on a second valuedetermined by adding the initially assigned time slot number to a firstvalue generated from a function having an input value determined byexclusive ORing (XORing) a binary sequence corresponding to thesub-frame number and an arbitrary binary sequence among binary sequenceshaving the same length as the binary sequence corresponding to thesub-frame number.
 15. The method as claimed in claim 14, wherein thefunction is represented by,${M\lbrack A\rbrack} = {\sum\limits_{n = 0}^{12}\; a_{n}}$ where A is avalue obtained by XORing the binary sequence corresponding to thesub-frame number and an arbitrary binary sequence among binary sequenceshaving the same length as the binary sequence corresponding to thesub-frame number.
 16. The method as claimed in claim 14, wherein thefunction is represented by,${M\lbrack A\rbrack} = {\sum\limits_{n = 0}^{12}\;{a_{n} \times 2^{n}}}$where A is a value obtained by XORing the binary sequence correspondingto the sub-frame number and an arbitrary binary sequence among binarysequences having the same length as the binary sequence corresponding tothe sub-frame number.
 17. The method as claimed in claim 14, wherein thefunction is represented by,${M\lbrack A\rbrack} = {\sum\limits_{n = 0}^{12}\;{a_{n} \times \left( {n + 1} \right)}}$where A is a value obtained by XORing the binary sequence correspondingto the sub-frame number and an arbitrary binary sequence among binarysequences having the same length as the binary sequence corresponding tothe sub-frame number.
 18. A method for randomly assigning uplinksub-frame time slots transmitting user data in an TDD (Time DivisionDuplexing) communication system which includes a plurality of frameshaving different frame numbers, each of the frames including a pluralityof sub-frames having different sub-frame numbers, each of the sub-framesincluding a plurality of time slots, and assigns user data of aplurality of IJEs (User Equipments) to the time slots in each sub-frame,the method comprising the steps of: creating a user data part bymultiplexing user data to be transmitted to a Node B, a TFCI (TransportFormat Combination Indicator) symbol for the user data, and a TPC(Transmission Power Control command) symbol for controlling transmissionpower of an uplink channel; and randomly assigning time slots fortransmitting the user data part in the sub-frames, based on a time slotnumber initially assigned for the user data part, a sub-frame number ata transmission point of the user data part, and the number of assigneduplink time slots in the corresponding sub-frame.
 19. The method asclaimed in claim 18, wherein the step of randomly assigning the timeslots comprises the step of assigning, as a time slot number fortransmitting the user data part, a fourth value determined by adding thenumber of downlink time slots in the sub-frame to a third value obtainedby performing a modulo operation with the number of the uplink timeslots on a second value determined by adding the initially assigned timeslot number to a first value generated from a function having an inputvalue determined by exclusive ORing (XORing) a binary sequencecorresponding to the sub-frame number and an arbitrary binary sequenceamong binary sequences having the same length as the binary sequencecorresponding to the sub-frame number.
 20. The method as claimed inclaim 19, wherein the function is represented by,${M\lbrack A\rbrack} = {\sum\limits_{n = 0}^{12}\; a_{n}}$ where A is avalue obtained by XORing the binary sequence corresponding to thesub-frame number and an arbitrary binary sequence among binary sequenceshaving the same length as the binary sequence corresponding to thesub-frame number.
 21. The method as claimed in claim 19, wherein thefunction is represented by,${M\lbrack A\rbrack} = {\sum\limits_{n = 0}^{12}\;{a_{n} \times 2^{n}}}$where A is a value obtained by XORing the binary sequence correspondingto the sub-frame number and an arbitrary binary sequence among binarysequences having the same length as the binary sequence corresponding tothe sub-frame number.
 22. The method as claimed in claim 19, wherein thefunction is represented by,${M\lbrack A\rbrack} = {\sum\limits_{n = 0}^{12}\;{a_{n} \times \left( {n + 1} \right)}}$where A is a value obtained by XORing the binary sequence correspondingto the sub-frame number and an arbitrary binary sequence among binarysequences having the same length as the binary sequence corresponding tothe sub-frame number.
 23. A method for receiving a downlink signal ofrandomly assigned sub-frame time slots transmitting user data in an TDD(Time Division Duplexing) communication system which includes aplurality of frames having different frame numbers, each of the framesincluding a plurality of sub-frames having different sub-frame numbers,each of the sub-frames including a plurality of time slots, and assignsuser data of a plurality of UEs (User Equipments) to the time slots ineach sub-frame, the method comprising the steps of: determiningreception sub-frame time slots in association with the randomly assignedsub-frame time slots, based on a time slot number initially assigned ata reception point of the downlink signal and a sub-frame number at thereception point; and demultiplexing the downlink signal received at thereception sub-frame time slots, and outputting user data, a TFCI(Transport Format Combination Indicator) symbol for the user data, and aTPC (Transmission Power Control) symbol for controlling transmissionpower of a downlink channel.
 24. A method for receiving uplink signalsof randomly assigned sub-frame time slots transmitting user data in anTDD (Time Division Duplexing) communication system which includes aplurality of frames having different frame numbers, each of the framesincluding a plurality of sub-frames having different sub-frame numbers,each of the sub-frames including a plurality of time slots, and assignsuser data of a plurality of UEs (User Equipments) to the time slots ineach sub-frame, the method comprising the steps of: determiningreception sub-frame time slots in association with the randomly assignedsub-frame time slots, based on a time slot number initially assigned ata reception point of the uplink signals and a sub-frame number at thereception point; and demultiplexing the uplink signals received at thereception sub-frame time slots, and outputting user data, a TFCI(Transport Format Combination Indicator) symbol for the user data, and aTPC (Transmission Power Control command) symbol for controllingtransmission power of an uplink channel.